A heater to be operated with liquid fuel in a vehicle is known from DE 10 2004 050 121 A1. A fluid supply system, which delivers the liquid fuel as a fluid between a reservoir and the heater, is associated with this heater. The system comprises a first fluid line leading to an on-off valve, a valve line leading from the on-off valve to the heater and a third valve line returning from the on-off valve to the reservoir. The on-off valve can be brought into two valve positions. In a first valve position, it connects the first fluid line to the second fluid line, so that the liquid fuel is delivered via the on-off valve to the heater by a fuel pump arranged in the first fluid line, while the third fluid line is closed. In a second valve position, the on-off valve closes the second fluid line and establishes a connection between the first fluid line and the third fluid line, so that a fluid circuit is formed, which comprises the first fluid line with the fluid pump located therein, the on-off valve, the third fluid line and the reservoir. An attempt is made in this manner to create defined conditions at the beginning of a combustion operation.
DE 10 2005 060 793 A1 discloses a fuel supply system, in which the liquid fuel contained as a fuel in a fuel reservoir is delivered via a fuel pump to a system area that is to be fed, i.e., an internal combustion engine. Two sucking jet pumps, into which branch lines branching off from the fuel pump lead, are associated with this fuel pump. During its operation, the fuel pump delivers fuel not only to the internal combustion engine, but also to the two sucking jet pumps, which deliver liquid fuel as a consequence of this into a swirl pot contained in the reservoir. The fuel pump takes the liquid fuel to be delivered to the internal combustion engine from this swirl pot.